1. Field of the Invention
The present invention relates to a job processing method for an information processing system which includes a plurality of information processing devices connected to a common transmission line. More specifically, the present invention relates to a job processing method for executing a job in a reliable manner, even if an abnormality occurs in the processing device executing the job, by use of the remaining processing devices.
2. Description of the Prior Art
In the case where a job request has occurred in an information processing system including a plurality of information processing devices, that job has been executed according to the prior art in the following different ways:
(1) the job is executed by the processing device which has detected the job request occurrence; or
(2) that processing device which detects the job request demands that another processing device perform the execution of that job so that the job may be executed by the other processing device.
In the aforementioned case (1), there arises a disadvantage in that the job is not executed if the processing device having detected the job request becomes abnormal and is disabled.
In the aforementioned case (2), the first processing device having referred the job execution to a second processing device keeps monitoring the second processing device to which the job has been referred. Therefore, when the second processing device having the task of executing the job becomes disabled, the first processing device can detect that disorder so that the job can be assigned another processing device for execution. However, there arises a disadvantage in that the job cannot be executed when both the first and second processing devices becomes disabled at the same time.
The present invention has been conceived to eliminate the disadvantages concomitant with the prior art thus far described and has an object to provide a job processing device for an information processing system, in which, even if an abnormality occurs in either the processing device which has detected the occurrence of a job request or a processing device to which the job execution has been referred by the former device, that job can be executed by means of the remaining processing devices.
According to the present invention, there is provided a job processing method for use in an information processing system including three or more information processing devices connected with a common transmission line:
(a) First of all, in the case where the occurrence of a job request is detected at one of the three or more processing devices, this condition is broadcast on the transmission line to the remaining plural processing devices;
(b) Next, job execution is started at a first processing device which is any one of the plural processing devices informed of the job request occurrence or the processing device having broadcast the job request occurrence;
(c) Then, the first processing device having started that job execution is monitored by the others of the plural processing devices which are not presently involved in that job execution, but have been informed of that job request occurrence; and
(d) The job is executed irrespective of the presence of an abnormal processing device in case a second processing device, which is one of the plural monitoring processing devices, detects an abnormality of the processing device executing that job.